| abstract |
A compound represented by the general formula (I) (wherein R1 represents C1-6 alkyl, etc.; R2 and R3 are the same or different and each represents hydrogen, etc.; Ra represents C1-6 alkyl, etc.; Arom represents aryl, etc.; A represents C1-6 alkylene; E represents a single bond, oxygen, sulfur, etc.; and X1 and X2 are the same or different and each represents oxygen or sulfur); or a pharmacologically acceptable salt or ester of the compound. |